Since his first writings, C. S. Peirce defended an unpsychological approach to logic. His authority was J. F. Herbart, who in his Lehrbuch zur Einleitung in die Philosophie had affirmed that “in logic it is necessary to ignore everything that is psychological.” This would become a standard reference for Peirce’s philosophy of logic. Moreover, it was from Herbart’s conception of apperception that Peirce inherited the “synechistic” law of mind first exposed in 1892. This paper explores Peirce’s lifelong “Herbartian” antipsychologism, reviews Herbart’s notion of apperception and indicates its significance for Peirce’s law of mind.